Chesterfield, Missouri (October 4, 2013)--Looking over a field wonít tell a farmer very much about whether that field holds soybean cyst nematode (SCN). Thatís why itís important for farmers to dig deeper for this disease, the No. 1 soybean yield robber.

It can be difficult to identify fields infested with SCN because the disease causes little damage to the above-ground plant, according to the University of Missouri Extension. But that doesnít mean it wonít cause soybean yield loss.

Farmers have several ways to manage and potentially prevent SCN, including:

1. Scout for symptoms of SCN. By doing so you may be able to detect SCN before it infests your field. To determine if your fields have SCN, you should scout for females (cysts) on the roots, monitor your soybean yield and have soil samples tested for the number and type of SCN present. By determining this information, you can find the right resistant variety to use.

2. Use resistant varieties. Different SCN-resistant varieties come with different levels of resistance. Before purchasing an SCN-resistant variety, make sure the variety you choose has a sufficient level of resistance to the SCN population in your field.

3. Rotate to non-host crops. By rotating your fields with crops that are not SCN hosts, such as corn, alfalfa, wheat, barley, potatoes, sunflowers, sugar beets and sorghum, you can prevent SCN from reproducing, and hopefully produce an SCN-free field when you rotate back to soybeans.

4. Maintain plant health. If your soybeans are experiencing stress due to drought, nutrient deficiencies, weed infestation, insects or other diseases, this can intensify the damage from SCN. Maintaining good soil fertility will also help enhance plant growth and minimize yield loss to SCN.

5. Control weeds. Spray to reduce weeds in fields because they too can be SCN hosts.

SCN is considered the most destructive soybean pathogen, causing nearly $1 billion worth of damage annually, according to the University of Minnesota Extension. It can be found in at least 31 states.

SCN can cause soybean yield losses of more than 30 percent, and in some sandy soils, total yield loss can occur. The severity of yield loss can be influenced by several factors, including weather, soybean variety and soil and other biological factors.